As a cofounder of a CDN company that pushed a lot of traffic, the problem with live streaming is that you need to propagate peak viewership trough a loooot of different providers. The peering/connectivity deals are usually not structured for peak capacity that is many times over the normal 95th percentile. You can provision more connectivity, but you don't know how many will want to see the event. Also, live events can be trickier than stored files, because you can't offload to the edges beforehand to warm up the caches.

So Netflix had 2 factors outside of their control

- unknown viewership

- unknown peak capacities outside their own networks

Both are solvable, but if you serve "saved" content you optimize for different use case than live streaming.